Staying cool.(Department)

Publication: OEM Off-Highway

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COPYRIGHT 2008 Cygnus Business Media

Staying cool

by Grant Suhre

A properly designed cooling system is critical to engine performance.

It is virtually impossible to overstate the importance of an engine's cooling system because it directly affects how reliable and durable the machine will be in the field. OEM engineers must work closely with their engine manufacturer and/or distributor on the design and selection of an engine's cooling system.

It's important for equipment engineers to understand the key components of the cooling system because of their effect on the equipment's overall performance.

The main job of the cooling system is to reduce engine temperature. The cooling system removes heat from the engine by transferring it from the engine to the coolant. Once coolant is moved to the radiator, the air temperature increases, decreasing the coolant temperature by 5 to 10 F. This process repeats itself, circulating coolant throughout the engine.

The core components of the cooling system include the radiator, the fan and its shrouding, coolant lines, coolant pump, thermostat, coolant jackets, and the charge air cooler. Some engines also utilize an exhaust gas recirculation (EGR) cooler. Most engine manufacturers don't supply components that are external to the engine, such as the radiator, directly from the factory. OEMs will typically need to work with their engine distributor or another resource to complete the cooling system.

Experts at John Deere Power Systems offer the following advice to help OEMs ensure that an application's engine and cooling system work together to keep the equipment running smoothly.

Aftercooling

An engine's aspiration can involve the cooling system and directly affects the equipment's performance.

Diesel engines can have four kinds of aspiration: natural aspiration, turbocharging, liquid-to-air aftercooling and air-to-air aftercooling. Liquid-to-air aftercooling and air-to-air aftercooling affect the engine's cooling system. Air-to-air aftercoolers and engine radiators require a fine balance between the systems to maintain optimum charge-air temperatures and coolant temperatures across the engine's operating range.

Air-to-air and liquid-to-air aftercooled engines have a higher power density...

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